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HNQ
12:57 AM
3
Q: Principle of stationary action vs Euler-Lagrange Equation

Akira D.SoulI am a bit confused as to what I should use to derive the equations of motions from the lagrange equation. Suppose I have a lagrange function: $$L(x(t), \dot{x}(t)) = \frac{1}{2}m\dot{x}^2-\frac{1}{2}k(\sqrt{x^2+a^2}-a)$$ Method 1: Principle of least action $$\delta L = \delta \dot{x}(m\dot{x...

 
 
6 hours later…
HNQ
7:06 AM
1
Q: If a photon truly goes through both slits (at the same time), then why can't we detect it at both slits (at the same time)?

Árpád SzendreiI am not asking about whether the photon goes through both slits, or why. I am not asking whether the photon is delocalized as it travels in space, or why. I have read this question: Do we really know which slit the photon passed through in Afshar's experiment? Which theory explains the path o...

 
 
1 hour later…
HNQ
8:07 AM
6
Q: Would an intelligent alien civilisation categorise EM radiation the same as us?

VeryCommonNameWe were taught at school that EM radiation can be categorised as radio waves, microwaves, infrared waves, visible light, ultraviolet radiation, X-rays, and gamma rays, but how arbitrary is this categorisation? I understand that for humans the 'visible light' category is an obvious, but how did s...

 
 
12 hours later…
HNQ
8:01 PM
1
Q: Why do we use the particular magnitude of a force to calculate work?

Alex ChashinI can't say I know physics very well. The most confusing concept for me as for now is potential energy. Often, when introducing potential energy of a gravitational force, the following example is used: imagine an object that has the mass of 1 kilogram that is lying on the earth. The gravitational...

 

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